Effect of ethanolic extraction, thermal vacuum concentration, ultrafiltration, and spray drying on polyphenolic compounds of tropical highland blackberry ( Rubus adenotrichos Schltdl.) by‐product

Optimization and component identification of ultrasound-assisted extraction of functional compounds from waste blackberry (Rubus fruticosus Pollich) seeds

BACKGROUND

Blackberry seeds, as a by-product of processing, have potential bioactive substances and activities. A response surface method was used to determine the optimal conditions of blackberry seed extracts (BSEs) with high 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity by ultrasound-assisted extraction (UAE). The composition and antioxidant capacity of BSEs were further analyzed.

RESULTS

The optimal conditions were material-to-liquid ratio of 0.07 g mL-1, ethanol concentration of 56%, extraction temperature of 39 °C and ultrasonic power of 260 W. Using these conditions, the extraction yield and total polysaccharide, phenolic and anthocyanin contents in BSEs were 0.062 g g-1 and 633.91, 36.21 and 3.07 mg g-1, respectively. The Fourier transform infrared spectra of BSEs exhibited characteristic peaks associated with polysaccharide absorption. The antioxidant capacity, DPPH and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, and ferric reducing antioxidant power of BSEs were 1533.19, 1021.93 and 1093.38 mmol Trolox equivalent g-1, respectively. The delphinidin-3-O-glucoside, paeoniflorin-3-O-glucoside and cyanidin-3-O-arabinoside contents in BSEs were 3.05,12.76 and 1895.90 ± 3.45 μg g-1. Five polyphenols including gallic acid, coumaric acid, ferulic acid, catechin and caffeic acid were identified and quantified in BSEs with its contents at 8850.43, 5053.26, 4984.65, 1846.91 and 192.40 μg g-1.

CONCLUSION

These results provide a method for preparing BSE containing functional components such as polysaccharides, phenols and anthocyanins through UAE, and BSEs have potential application in food industries. © 2024 Society of Chemical Industry.

The Kinetics of Two-Step Ellagitannin Extraction from the By-products of Selected Processed Fruits of the family Rosaceae

The paper presents the kinetics of two-step ellagitannin (ET) extraction with an aqueous acetone solution from two technological types of pomace from selected berry fruits of the Rosaceae family. ETs were identified and quantified using HPLC–MS and HPLC–DAD. The results revealed the extraction kinetics of total ETs, their high and low molecular weight fractions (≤ 1569 Da and > 1569 Da), and individual ETs characteristic of the examined fruits. ET extraction proceeded at a faster rate in the first step, regardless of the tested pomace. For all pomace variants, the mean extraction half time t1/2 was 48 min in the first step and 70 min in the second step. The fruit species and the technological type of pomace were not found to exert a definite effect on the kinetics of ET extraction. Statistical analysis demonstrated that the molecular weight of ETs did not influence the kinetics of their extraction, either. It was shown that the technological type of pomace had a significant impact on the extraction rate of both low molecular weight (LMW) and high molecular weight (HMW) ETs in the first extraction step, with the mean t1/2 being 44 min for pomace from juice production and 63 min for pomace from puree production.